1. Field of the Invention
The invention relates to a coaxial electrical connector, more particularly to a coaxial electrical connector with a switching function.
2. Description of the Related Art
U.S. Pat. No. 6,547,592 discloses a coaxial electrical connector element that provides a switching function and that comprises a central conductor, an external conducting body forming a ground contact, a contact piece, and a conducting socket. The conducting socket can move axially about the central conductor, between a first position, in which it simultaneously bears against the central conductor and the contact piece, and a second position, in which it is spaced from the contact piece. A return member is provided for urging the conducting socket into its first position. The return member consists of an elastically deformable tubular piece engaged around the central conductor. The tubular piece is placed in the conducting body so as to be held therein by a cylindrical end part while still being able to deform radially owing to axial displacement of the conducting socket during mating with a complementary connector element. The socket is designed to push the free end of the tubular piece axially backward.
In view of the foregoing, the aforesaid connector element provides a switching function for signal transmission between the complementary connector element and the central conductor or between the contact piece and the central conductor.
The aforesaid connector element permits signal transmission through the central conductor that is surrounded by the return member made of an insulator material. However, according to studies in radio frequency design principles, the insulating effect attributed to insulator materials is inferior to that achieved by air. Therefore, a radio frequency signal conducted by the central conductor will be unavoidably attenuated through the return member and the external conducting body. Based on actual tests, under the condition VSWR<1.5, a radio frequency that can be conducted by the aforesaid connector element has a maximum value of 3 GHz. Therefore, an improvement on the applicable operating frequency of the coaxial electrical connector element is highly desired.
On the other hand, the switching function of the aforesaid connector element relies on the resiliency of the return member, which also provides an insulating function. These requirements restrict the return member to be made from a material, such as rubber, which does not have resiliency and adaptability to ambient environment conditions, such as temperature, superior to those of a metal compression spring. Therefore, the biasing effect for urging the conducting socket is prone to degrade after a period of use due to elastic fatigue. Lastly, the switching function of the aforesaid connector element is possible due to the cooperative action of numerous components, such as the central conductor, the return member and the conducting socket, which is relatively complicated and prone to malfunction.